This invention relates to solar energy and more particularly to apparatus for use in a solar energy system, including a flat plate solar collector, heat exchange unit, a regenerator for use in conjunction with solar driven air conditioning systems, and an improved heat storage apparatus.
With increased cost of energy sources, especially fossil fuels, and with apprehension concerning fissile fuel sources, there is greater stress being placed on the utilization of solar energy as a suitable source. Although numerous proposals have been made on efficient utilization of solar energy and although many solar energy systems are already in existence, none of these have been widely accepted, mainly because of the great cost of such systems, the excessive weight requirement of the solar collector and other parts of the system and the rather limited efficiency provided by such systems.
Most of the solar energy systems use collectors to trap the sun's heat and transfer it to a flow medium usually either air or water. The flow medium conveys the heat and utilizes it either directly or through further conversion for hot water heating, area heating, and even cooking. It also stores a portion of the absorbed heat in a storage device from which the heat can be withdrawn during the night.
The solar collectors which are commonly used are of various types. One type is referred to as the flat plate solor collector. Some of these use plastic absorber sheets for low cost and reduced weight. However, there results a great deficiency in performance and longevity of such collectors. Those collectors which have high efficiency performance use copper absorber sheets. However, these are extremely heavy and require extra support in order to retain such collectors. On top of the collectors there is usually placed a sheet of flat glass which is generally thick and heavy or else flat plastic is utilized. Both of these materials tend to sag unattractively across the collector span. Additionally, the glass is frequently unsupported and accordingly tends to be fragile.
In addition to problems with existing flat plate solar collectors, other problems with solar energy systems relate to the fact that such systems may find use for heating, however a separate energy source is generally needed for air conditioning. In those colder climates where only heating is needed and generally air conditioning is not utilized, a high efficient solar energy system may be useful. On the other hand, in those areas where both heating and air conditioning are generally provided in housing for alternate use during the year, the use of a solar heating system is costly since a separate source of energy must be provided to drive the air conditioning. This is of particular concern since the solar energy is generally strongest in those areas which need heat the least and on the other hand require more air conditioning. Accordingly, while the sun is available in certain areas, rather than heat being required, air conditioning is needed.
Another drawback with existing solar energy systems concerns the storage of the heat for nighttime use, or darkened use. Most present storage units use water or other such similar medium to store the heat by raising the temperature of the water. The heat is stored in such water and during nighttime or darkened periods the heat is extracted by utilizing the heat and lowering its temperature. However, the efficiency of such storage of heat is limited and the size of a storage tank needed to store sufficient heat is generally massive.
Further problems existing with present solar energy systems concern the heat exchanger. Once the heat in the flow medium is obtained by means of the solar collector, the heat from the flow medium must be extracted for use in connection with heating, hot water systems, and other similar devices. For extracting the heat, a heat exchanger is generally used. Generally utilized heat exchangers are low in efficiency as a result of which much of the heat is not converted to useful purposes and is rather wasted.
Accordingly, although solar energy is available, its use has been limited because of numerous problems with present day equipment. Improvement in such equipment can result in beneficial utilization of solar energy as a source of heating.